Question

A large tank filled with water is to be emptied by removing 1/5th of the water present in it everyday. After how many days will there be closest to 25% of the water left in the tank

Answer 1

Let the three angles in a right angle triangle shaped garden be A, B and C. If three angles in a right triangle are in arithmetic progression, the middle valued angle must be less than 900 (three times the middle valued angle = 1800).

So the angles are, 900 + (900 - x) + (900 - 2x) = 1800,

or, 3x = 900,

or, x=300.

The angles are then, 300,600,900.



The smallest 10m side is opposite to the smallest angle of 300. So, longest side hypotenuse AC=ABsin300=20m and the base,

BC=ACcos300

or, BC=20×√32≅20×.85≅17m.

The perimeter is,

P=AB+CA+BC

Or, P≅10m+20m+17≅47m

Answer: The value near 47m, that is Choice b: 47.32